package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;
    @Autowired
    private ISeckillVoucherService iSeckillVoucherService;
    @Autowired
    private RedisIdWorker redisIdWorker;
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    // 获取队列中的订单信息 XREADGROUP
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 判断消息是否成功
                    if (list == null || list.isEmpty()) {
                        // 没有消息，执行下一次
                        continue;
                    }
                    // 解析消息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 有消息，创建订单
                    handleVoucherOrder(voucherOrder);
                    // ACK 确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }
        private void handlePendingList() {
            while (true) {
                try {
                    // 获取队列中的订单信息 XREADGROUP
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 判断消息是否成功
                    if (list == null || list.isEmpty()) {
                        // 没有消息，执行下一次
                        break;
                    }
                    // 解析消息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 有消息，创建订单
                    handleVoucherOrder(voucherOrder);
                    // ACK 确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }
    }
   /*private BlockingQueue<VoucherOrder> taskQueue = new ArrayBlockingQueue<>(1024*1024);

    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true){
                // 获取队列中的订单信息
                try {
                    VoucherOrder voucherOrder = taskQueue.take();
                    // 创建订单信息
                    handleVoucherOrder(voucherOrder);
                } catch (InterruptedException e) {
                    log.info("处理订单异常", e);
                }
            }
        }
    }*/

    /**
     * 创建订单
     * @param voucherOrder
     */
    private void handleVoucherOrder(VoucherOrder voucherOrder){
        // 获取用户信息
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:oder" + userId);

        boolean success = lock.tryLock();
        if (!success) {
            log.error("不允许重复下单");
            return;
        }
        try {
            createVoucher(voucherOrder);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            lock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        // 通过redis，查询库存信息，和代金券的用户是否有重复下单的问题
        // 获取用户id
        Long userId = UserHolder.getUser().getId();
        // 订单id
        long orderId = redisIdWorker.nextId("order");

        log.info("userID:{}", userId);
        // 执行lua脚本
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
                );
        assert result != null;
        int r = result.intValue();
        if (r!=0){
            return Result.fail(r==1?"库存不足":"不能重复下单");
        }
        return Result.ok(orderId);
    }


    /*@Override
    public Result seckillVoucher(Long voucherId) {
        // 通过redis，查询库存信息，和代金券的用户是否有重复下单的问题
        // 获取用户id
        Long userId = UserHolder.getUser().getId();
        // 执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString());
        assert result != null;
        int r = result.intValue();
        if (r!=0){
            return Result.fail(r==1?"库存不足":"不能重复下单");
        }
        // 为0，有购买资格，把下单信息保存到阻塞队列里面
        long orderId = redisIdWorker.nextId("order");
        // TODO:保存组赛队列
        // 1.创建订单信息
        VoucherOrder voucherOrder = new VoucherOrder();
        long nextId = redisIdWorker.nextId("oder");
        voucherOrder.setId(nextId);
        voucherOrder.setVoucherId(voucherId);
        voucherOrder.setUserId(userId);
        // 2.创建阻塞队列
        // 添加到阻塞队列
        taskQueue.add(voucherOrder);
        // 获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }*/

    public void createVoucher(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        // 创建锁对象
        RLock redisLock = redissonClient.getLock("lock:order:" + userId);
        // 尝试获取锁
        boolean isLock = redisLock.tryLock();
        // 判断
        if (!isLock) {
            // 获取锁失败，直接返回失败或者重试
            log.error("不允许重复下单！");
            return;
        }

        try {
            // 5.1.查询订单
            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
            // 5.2.判断是否存在
            if (count > 0) {
                // 用户已经购买过了
                log.error("不允许重复下单！");
                return;
            }

            // 6.扣减库存
            boolean success = iSeckillVoucherService.update()
                    .setSql("stock = stock - 1") // set stock = stock - 1
                    .eq("voucher_id", voucherId).gt("stock", 0) // where id = ? and stock > 0
                    .update();
            if (!success) {
                // 扣减失败
                log.error("库存不足！");
                return;
            }

            // 7.创建订单
            save(voucherOrder);
        } finally {
            // 释放锁
            redisLock.unlock();
        }
}
}


    /*@Override
    public Result seckillVoucher(Long voucherId) {

        // 查询代金券的信息
        SeckillVoucher seckillVoucher = iSeckillVoucherService.getById(voucherId);
//        log.info("当前时间：{}", LocalDateTime.now());
//        log.info("开始时间：{}", seckillVoucher.getBeginTime());
//        log.info("结束时间：{}", seckillVoucher.getEndTime());
        // 秒杀是否开始或者结束
        if (seckillVoucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }
        if (seckillVoucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束");
        }
        // 查看库存
        if (seckillVoucher.getStock()<1) {
            return Result.fail("库存不足");
        }
        // 一人一单
        Long userId = UserHolder.getUser().getId();
        // 不使用synchronized，使用自己的🔒
        // 使用redisson的🔒
        // SimpleRedisLock iLock = new SimpleRedisLock(stringRedisTemplate, "oder"+userId);
        RLock lock = redissonClient.getLock("oder" + userId);
        // boolean success = iLock.tryLock(1200);
        boolean success = lock.tryLock();
        if (!success) {
            return Result.fail("用户已经成功抢到！请勿重复提交");
        }
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucher(voucherId);
        } catch (IllegalStateException e) {
            throw new RuntimeException(e);
        } finally {
            lock.unlock();
        }
        *//*
        在不同的进程中，也就是分布式的服务器当中，JVM是不一样的，所以它的synchronized也是不一样的
        所以需要分布式🔒来解决多服务器的问题，分布式🔒满足所有的服务器都可以监视这个🔒，这样就保证了
        分布式服务器不同进程的串行运行。
         *//*

//        synchronized (userId.toString().intern()){
//            // 获取代理对象（事务）
//            // 只有代理类才拥有事务功能
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucher(voucherId);
//        }
    }*/

